Question

我有两个班，即Person和Language。每个语言都有创建者和更新者，他们都来自Person类。我想通过子节点查询父节点的属性，反之亦然。

人类

class Person
  include Mongoid::Document
  field :first_name, type: String
  field :last_name, type: String

  has_many :created_languages, class_name: 'Language', inverse_of: :created_by, foreign_key: 'created_by_id', autosave: true
  accepts_nested_attributes_for :created_languages

  has_many :updated_languages, class_name: 'Language', inverse_of: :updated_by, foreign_key: 'updated_by_id', autosave: true
  accepts_nested_attributes_for :updated_languages
end

语言课

class Language
  include Mongoid::Document

  field :content, type: String

  belongs_to :created_by, class_name: 'Person', inverse_of: :created_languages, foreign_key: :created_by_id, autosave: true
  accepts_nested_attributes_for :created_by

  belongs_to :updated_by, class_name: 'Person', inverse_of: :updated_languages, foreign_key: :updated_by_id, autosave: true
  accepts_nested_attributes_for :updated_by
end

我想在Rails应用程序中查询的内容如下：即在Rails控制台中：

ruby 2.0.0p451 > a = Person.create!(first_name: "Marco", last_name:"Reus")
ruby 2.0.0p451 > b = Language.create!(content: "German", created_by_id: a.id, updated_by_id: a.id)
ruby 2.0.0p451 > a.created_languages (now works)
ruby 2.0.0p451 > a.updated_languages (now works)
ruby 2.0.0p451 > b.created_by (now works)
ruby 2.0.0p451 > b.updated_by (now works)

我以前收到以下错误。通过上面的代码，它就解决了。

Mongoid ::错误:: AmbiguousRelationship：
问题：模糊关系：created_languages，：在Person上定义的updated_languages。

摘要：当Mongoid尝试在内存中设置关系的逆文档时，需要知道它属于哪个关系。设置：updated_by时，Mongoid在类Language上查找匹配关系，但是找到了可能匹配的倍数:: created_languages，：updated_languages。

解决方案：在关于语言的：updated_by关系中，您必须添加：inverse_of选项以指定Person上的确切关系：updated_by。

Answer 1

您还应该为所有这些包含inverse_of：

has_many :created_languages, class_name: 'Language', :inverse_of => :created_by

belongs_to :created_by, class_name: 'Person', :inverse_of => :created_languages

希望它有所帮助。

访问Mongoid中的父子属性

1 个答案: